Gear pump seal



Jan. 11, 1938. G, F, MAGLQT'' 2,105,428

GEAR PUMP S EAL Filed June 2, 1954 IN V EN TOR.

A T TORNEYS.

Cil

Patented Jan. 11, 1938 UNITED STATES GEAR PUMP SEAL George F. Maglott, Cranston, R. I., assignor to Brown & Sharpe Manufacturing Company, a corporation of Rhode Island Application June 2, 1934, Serial No. 728,798 4 Claims. (Cl. 286-7) This invention relates to a gear pump for pumping liquid, more particularly aliquid having lubricating properties such as fuel oil for oil burners; and has for one of its objects the provision of a seal which will both prevent the escape of the oil from pressure developed on the inside of pump and prevent any suction developed within the pump from drawing in air.

Another object of the invention is the provision of a seal which will be unaiected by the running out of line of the drive shaft for driving the pump.

` Another object of the invention is the provision of a common means which will assist the seating of the seal against pressure developed in the pump and also assist the seating of the seal against suction developed in the pump.

Another object of the invention is the circulation of the lubricant about the. moving parts and yet maintaining a seal 'of the lubricant in the pump casing.

Another object of the invention is the provision of a circulation of the material pumped in such a manner that it will lubricate the moving parts in a small pump by arranging certain of the conduits for the lubricant through the moving parts as distinguished from through the fixed part of the casing itself. v

Another object of the invention is to cause the lubricant circulation to assist in taking from the pressure seal some of the pressure which might otherwise be caused to be exerted thereon and thus reduce a chance of leakage through this seal.

Another object of the invention is the arrangement ofthe parts so as to maintain a hydrostatic balance of pressure on both sides of the pumping elements.

A further object of the invention is the provision of a pump the parts of which are the same regardless of the direction in which it is to operate which may be elected in finishing by merely choosing the Aarrangement of certain of the formed openings therein.

.With these and other objects in view, the in Fig. 3 is a sectional view on line 2-2 of Figure 1; v

Fig. 4 is a perspective view showing some of the proper seal about the'drive shaft which extends Y through the casing and operates one of the gears.

.If this seal were not tight when pressure of the liquid is developed in the pump, the liquid will be forced out about the drive shaft, whereas if the pump were not tight when there is a suction developed in the' pump casing, air will get in.

With a small bubble of air'in the pump, 'the pump will hammer and knock and run noisy for a considerable length of time. This seal is often caused to be imperfect by reason of the wobbling or the'getting out of line of the drive shaft to which the seal is frequently attached, and in this case I have provided a seal which is independent of the alignment of the drive shaft so that should the drive shaft be out of true line, the seal will be effectual to maintain the seal in the pump.

Also, there must be some means provided for lubricating the operating parts of a gear pump of this character. Frequently, the liquid which is to be pumped is of a lubricating quality, such for instance as the pumping of oil and where this is the case, as in the uses for which the present pump is particularly designed, a circulation is provided of this liquid about the moving parts so that fresh liquid is continually supplied to these parts to afford a more perfect lubrication rather than a stagnant lubrication which occurs in some pumps, in which case the oil will lose some of its lubricating properties and permits heating within the pump.

Sometimes in pumps of this character where there is a circulation of the oil, the oil is extruded out of the pump and lost, whereas this invention contains the oil at al1 times in the pump and seals it against escape.

Also, in small pumps it is rather difficult to provdea sufficient amount of stock for the formation of a conduit for the lubricant, and in order to economize space, I have provided a channel through the drive shaft which operates the gears of the pump and by which'a very emcient circulation is provided, and I have so arranged the circulation of the liquid in the pump that it cooperates with the seal to effect a. more .complete seal by relieving pressure on the seal during the running of the pump.

Further, by my arrangement and transmission of pressures, I maintain a hydrostatic balance in the pump on both sides of the pumping elements; and the following is a more detailed description of the present embodiment of this invention, illustrating the preferred means by which these advantageous results may be accomplished:

With reference to the drawing, I@ designates the body section of the pump, which is provided with an opening housing the gears II and I2, which mesh together and about which there is left a suction pocket I3 and a pressure pocket I5 for the entrance and delivery of the liquid to be pumped. At either side of the body element, I provide cap sections or closure members in one of which there is located suitable discharge and suction conduits.

One end cap section is designated I5, and the other end cap section I6 which'also has formed therewith a bracket portion Il in which the sealing and driving means are largely mounted. The cap sections I5 and I6 are held assembled on either side of th/e body section III by suitable bolts I8 and I9 extending through one of the cap sections, through the body section and threaded into the other cap section, whereby the sections are held in assembled relation sufficiently tight so that there will. be no leaking of air into or pumping of the liquid out of the casing.

Pumping elements or gears II and I2 may be made integral with or mounted on shafts 2|J^and 2| to which they may be securely xed against relative rotation. These shafts have bearings in the opposite cap sections; thus shaft 20 has' `a bearing 22 in the cap section I5, and 23 in the cap section I6, while the shaft 2| has a bearing pressure pocket |4. Suitable connection may be had to these conduits by means of the threaded bores`28 and 29 for the intake and delivery of the liquid to be pumped.

The gear or pumping element Il is driven through its shaft 20 by means of a drive shaft 30 which is connected to the shaft 20 through a sealing means which consists of a disc 3| and a disc 32, each provided Iwith tongues 33 and 34, which t into slots 35 and 36 in the coupling member 31, there being a helical spring 38 encircling the coupling member and engaging the inner surfaces 39 and 40 of the discs tending to force them apart. The sealing unit is rotatably mounted in a bore 4| in the portion I1 of the cap section I6,

. the end of this bore being provided with a finished spective slots 35 and 36, although not sufficient to force the discs into rm engagement with the coupling member 31. The inner end 45 of this sleeve 44 provides a finished seat against `which the finished surface 46 of the disc 32 engages to form a seal. The dis'c 32 is also of a size to be guided in its rotation by the bore 4|. The Sleeve arcade-ae dit is provided with a ange @l at its outer end, and is held in position by suitable bolt 38. 5

The sealing unit is connected tothe shaft 28 by a key 5I entering a slot or recess i9 in the shaft 20and slot or recess 58 in the disc 3|, and

of a length and size to more' or less loosely fit therein and yet maintain its driving position. 'I hus any rotation of the sealing means will cause a rotation of the shaft 25 while allowing the shaft 2@ to be entirely independent of the Isealing means so that any irregular running of the parts within the pump need not rock the seal from its seat.

The sealing means is driven through the tongue 52 on shaft 35 exten-ding into the slot or recess 53 in the disc 32. This slot is sufficiently large so that there may be a rocking of the shaft 35 in the slot and any irregularity in alignment with the shaft 30 will not be communicated to the disc 32 and thus accurate alignment of the shaft or true running in its bearings is not essential to the maintaining of this seal in its operating or working position. The shaft 35 is bushed as at 56. Oil is fed to the bearing through the opening which is closed by a set screw 55 to keep out foreign matter. A shoulder 56 fixed on the shaft 30 is engaged by a plate 5T, which plate is held in place by reason of bolts d8 and which in turn serves to secure the sleeve and bushing in place on the portion I'I of the cap section I 6.

Should any pressure be exerted on the sealing means from the inside outwardly and liquid be forced by the first disc 3 then the second disc 32 would be forced more tightly to its seat by the addition of such pressure assisted. by the spring 38, and thus from the inside provide a tight seal between the surfaces 45 and 46. Such pressure might occur from a head existing in the storage tank when the pumping elements are not rotating. It is `also of importance that the seal be maintained against a low pressure developed in the pump from drawing in air due to a greater pressure outside, and in this case, the reverse will be true in that any air entering about the shaft 30 may pass the first disc 32, but this outside pressure will be exerted against the surface 39 of disc 3| to force the disc 3| more rmly to its seat, also assisted by spring 38,and thus effectively prevent entrance of air into the pump, which might cause it to knock. Thus, this spring acts inboth directions to assist' in preserving the seal in the pump, while both discs are unaifected by any of theoperating parts which is very often detrimental to pumps of this character.

This particular pump is designed for pumping oil aliquid having lubricating properties and utilization may be made of the liquid for the lubrication of the moving parts of the pump, and I have taken advantage of this by providing certain channels to maintain a circulation of the liquid to be pumped about the bearings for the shafts 20 and 2|. In the casing, I have pro vided a conduit 60 which, as shown in Figure 1, is formed in the cap section l6'and extends upwardly from the y pocket at the end of shaft 2| to connect with the pocket at the end of the other shaft-20, and in fact, in order that I'may provide such a conduit,I have drilled the casing from the outside and then blocked up theouter end of this conduit as at 6|. I have also provided conduits or openings 62 through the shaft 20 and a conduit 63 through the `shaft 2|, also a conduit in the casing from the'left hand end of the shaft 2|! to thesuction chamber I3, which conduit I designate 64. By this arrangement, any liquid which seeps into bearing 24 from the gear I2, will Work its way along this bearing dto the pocket 65 at the end of shaft 2|, thence through the hole 63 in the shaft 2| to the ypocket 66 at conduit 64. Any liquid Working into the bearing,

23 Will be conveyed to the end of the shaft and y thence through a hole 62 to this conduit 64, while any liquid working into the bearing 22 will be conveyed to the .pocket 68 Which directly connects with conduit 64 and thus to the suction chamber. Thus it will be seen that all thexbearings are connected to the suction side of the pump, and any liquid leaking in from the pressure side will be drawn back to this suction side, and there will be provided a continuous circulation of liquid about these bearings in the chamber.

A chamber or pocket 59 at the right hand'end of shaft 2D is in communication with the port 6d and the suction chamber, and thus there is a vcontinual moving of any liquid from this pocket 69 towards the suction side of the pump andaway `from the disc 3|, and the continual movement away from this disc tends to lessen the pressure on the disc, and thus this circulation assists in relieving any pressure in the pump tending to force any liquid out of the pump.

Further, by my means of the arrangement of parts and circulation above mentioned, I maintain a perfect axial hydrostatic balance of pressures on either side of each of the pumping elements. Each area is fully balanced both on the pumping elements or gears themselves, as well as the pressures on the shafts 2@ and 2i, and thus this pump will operate a far greater length of time by reason of this balanced pressure than Where the pressure is greater on one side of the pump element thanon the other, forcing it towards some surface which mustreceive the thrust communicated to it.

Another feature of the present construction is that by the use of the same gears and the same castings, I may provide a pump which. may be ar-I ranged to run in a right or left hand direction, although the chosen direction must be determined before the pump is finished, as I must of necessity place the bore Sii on one side or the otherdepending upon the direction the pump is to be run; for instance, in Figure 2, the suction conduit is said to be 2t and the bore @il must connect the bearing 22 with the suction side of the pump, thus if I desire to change the direction of rotation of the pump elements, it will be optional forms of construction without anymaterial changes of construction.

The foregoing description is directed solely towards the construction illustrated, but 'I desire it to be understoodv that I reserve the privilege of resorting to all the mechanical changes t which the device is susceptible. the

invention being dened and limited only by the terms of the appended claims.

I claim:

1. In combination, a casing provided with a bore and a pairof opposed end seats, a shaft rotatably mounted in said casing, a drive shaft rotatably mounted in said casing and extending along said bore in a direction towards the first shaft/but terminating short of said shaft to leave a space therebetween, and sealing drive means through which said drive shaft and the other shaft are connected, said sealing drive means being interposed entirely between the ends of said shafts and comprising a .pair of movable discs in engagement with said seats, a coiled spring between said discs for exerting pressure in opposite directions against said discs to force them into sealing engagement with said seats, tongues on said discs, and a coupling member having slots to receive said tongues on the discs and located within and axially of said spring for connecting said discs for the transmission of rotation from one to the other. n

2. In combination with a casing provided with an elongated cylindricalI bore having a pair of opposed seats, of a shaft rotatably mounted in said casing and provided with a tongue extending in said bore,`a drive shaft having a tongue and rotatably mounted in said bore, said drive shaft extending along the bore of said casing in a direction towards the first shaft but terminating short of said shaft to leave a space therebetween, and sealing drive means through which said drive shaft and the other shaft are connected for rotation, said sealing drive means being an independent unit entirely disposed between the ends of said shafts and comprising a pair of discs in engagement with said seats and of such size as to be guided in rotation by said bore, a helical spring mounted between said discs and axially thereof for exerting pressure in opposite directions against said discs to force them against said seats, tongues on said discs, and a coupling member having slots to receive the tongues of said discs, said member being axially located within said spring for connecting said discs for the transmission of rotation from one to the other, said discs having outwardly facing slots to receive the tongues provided on said shafts for the transmission of rotation from one'shaft to another.

.3. The combination with a casing having an elongated cylindrical bore therein within which is contained a pair of opposed annular seating surfaces, of a shaft rotatably mounted in said casing and extending into said bore, a drive shaft in axial alignment with said first shaft,said drive shaft being rotatably mounted in said casing and extending inwardly along said bore towards the first shaft but spaced therefrom, and sealing drive means within said casing in axial alignment with said shafts and interposed between the ends of the lati. er for transmitting rotary motion,.said sealing drive means comprising a pair of longitudinally movable discs having tongue and groove driving connection with the ends of said shafts and between which said discs'are solely movable forv longitudinal movement, a coupling member having tongue and groove driving connection with said discs and co-axial therewith,.and a coiled spring surrounding said coupling and interposed between the inner end faces of said discs for constantly exerting endwise pressure upon said discs to move them in opposite directions and into sealing engagement With the said casing seats.

4. In a device of the character described, the

combination with a casing having an elongated cylindrical bore therein the inner end wall of which is provided with an annular seating surface and a shaft opening, of a shaft extending through said opening into said bore and terminating close to said seating surface, a sleeve within said bore and having an end seating surface thereon, a drive shaft journaled in said sleeve and in axial alignment with said rst shaft, said drive slaft extending inwardly along -said borel towards said rst shaft but spaced therefrom, and a sealing drive device within said bore and comprising a pair of spaced longitudinally movable disc members having a coupling sleeve interposed therebetween, said drive device being arranged in axial alignment with said shafts and entirely interposed betwen the ends of the same for trans-v mitting' rotary motion, said discs being of such size as to be guided by the bore in their rotation therein, said discs having/a sealing surface on their outer ends, one of which is adapted to engage the seating surface of the inner wall of said bore and the other to engage that on the end `of said sleeve, a coiled spring surrounding said coupling and interposed between the inner end fa es of said discs to exert end-wise pressure for fo cing the discs apart and in sealing engagement with said seating surfaces, said discs having tongue 'and groove driving connection with said coupling and said shafts.

GEORGE F. MAGLOT'I". 

